Treating severe drug-induced hyperthermia with an ice-water bath
February 20, 2015, 7:23 pm
Ice water submersion for rapid cooling in severe drug-induced hyperthermia. Laskowski LK et al. Clin Toxicol 2015 Mar;53:181-184.
There is still debate about the optimal method of cooling severely hyperthermic patients, such as those with core temperature > 104oF (40oC) who are exhibiting changes in mental status. Some common techniques include ice packs to the groin and axillae, cooling blankets, along with convection (evaporation) techniques such as cool sprays and fans. There is little debate, however, about the proposition that the faster these extremely hyperthermic patients are cooled the better the outcomes.
This fascinating paper present 2 spectacular cases of drug-induced severe hyperthermia treated by submerging the patient in an ice-water bath:
- A 27-year-old man was brought to the hospital with agitation after ingesting 4-fluoroamphetamine. (This was confirmed in the laboratory.) His rectal temperature was 106.5oF (41.4oC). He was immediately placed in an ice water bath, with core temperature measured every 5-60 seconds. After 22 minutes in the bath, he core temperature was 99.3oF (37.4oC). The patient received a total dose of 28 mg midazolam while submerged and did not exhibit shivering. On the second hospital day, he signed out against medical advice.
- A 32-year-old man was brought to hospital because of agitation and hallucinations after using cocaine. His rectal temperature was 112oF (44,4oC)!! He was paralyzed, intubated, and place in an ice-water bath. After 20 minutes in the bath, his core temperature was 102oF (38.8oC.) He was discharged after 10 days in hospital”in stable condition,” although no mention is made of his mental status.
These temperatures are impressive, especially in the second case. (I think 112oF is hot enough to sous vide a salmon.) In the discussion section, the authors describe their technique:
The steps to performing ice water submersion are straight-forward. Once hyperthermia is documented, the patient should be immediately undressed, wrapped in a sheet, and place in a water-impermeable bed (when available), while indirect patient care staff fill large plastic bags with ice to cover and surround the patient. Important nursing and patient care technician roles include establishment of IV access, administration of medication, and placement of cardiac leads, pulse oximetry and a rectal probe for continual core temperature monitoring. Benzodiazepines may be indicated to treat psychomotor agitation. Rapid sequence incubation and advanced cardiac life support measures, if indicated, can and should be performed with the patient in the ice bath. While a lack of evidence exists to guide a specific endpoint temperature, we recommend at endpoint core temperature of 39oC (102.2oF), at which point the patient should be moved to a new hospital bed and dried completely, to avoid an overshoot towards hypothermia.
In an editorial commentary piece, Dr. Edward Otten from the University of Cincinnati states that although defibrillation would be difficult to perform on a patient in an ice-water bath, significant cardiac arrhythmias are rare in hyperthermia. He also suggests that an esophageal thermometer might be a preferred method of measuring core temperature, since it does not come into contact with ice water.
This is a case series of only 2 patients, but very interesting and worth reading.